Cellular Form and Function
Reference Book:
Anatomy & PhysiologyThe Unity Of Form And Function
Ninth Edition;Kenneth S. Saladin
Lecture delivered by
Dr Vini Gautam
Lecturer
Department of Biomedical Engineering
2
Quick Quiz
Quick Quiz
3
4
About 200 types of cells in human body with varied shapes
Note: A cell’s shape can appear different if viewed in a different type of section (longitudinal versus cross section)
5
Human cell sizes
6
7
a: © AlvinTelser/McGraw-Hill Education;b: ©BiophotoAssociates/Science Source
8
1. Plasma (cell) membrane
2. Cytoplasm
Extracellular fluid (ECF)
9
Plasma membrane = border of the cell
10
Access the text alternative for slide images.
11
Phospholipids
12
Cholesterol
Glycolipids
13
Membrane proteins
Integral proteins—penetrate membrane
Peripheral proteins
14
Figure 3.6
Access the text alternative for slide images.
15
Access the text alternative for slide images.
To ‘stick’ cells inplace
What kind of cellam I?
Involved in the action of drugs
19
Figure 3.8
Access the text alternative for slide images.
20
Involve TRANSPORT across the plasma membrane
Crucial to nerve and muscle function
© McGraw Hill
21
See poll for a quick quiz and answer
22
Involve TRANSPORT across the plasma membrane
Crucial to nerve and muscle function
23
Plasma membrane (and organelle membranes) areselectively permeable—allowing some things through, butpreventing others from passing
Passivetransport requireno energy(ATP)
Activetransportconsume energy(ATP)
24
Filtration—particles are driven through membrane byphysicalpressure
Examples
25
Figure 3.13
Access the text alternative for slide images.
26
Simple diffusion—net movement of particles from place ofhigh concentration to place of lower concentration
Substances diffuse down theirconcentration gradient
27
Factors affectingdiffusion ratethrough a membrane
28
29
Osmosis—netflow of waterthrough a selectively permeablemembrane
Crucial consideration for IV fluids
Osmotic imbalances underlie diarrhea, constipation, edema
Cool fact:While water can diffuse through phospholipid bilayers,osmosis is enhanced by aquaporins (channel proteins in membranespecialized for water passage)
30
Tonicity—ability of a surrounding solution (bath) to affect fluid volume andpressure in a cell
Hypotonic solution—causes cell to absorb water and swell
Hypertonic solution—causes cell to lose water and shrivel (crenate)
Isotonic solution—causes no change in cell volume
31
(a-c): © David M. Philips/Science Source
Swollen cell
Crenated cell
32
One osmole (osm) = 1 mole of dissolved particles
Osmolarity = number of osmoles per liter of solution
33
Transport proteins in membrane carry solutes into or out ofcell (or organelle)
Specificity
Saturation
34
Three kinds of carriers
Three mechanisms of carrier-mediated transport
35
Facilitated diffusion: a carrier moves solute down itsconcentration gradient
Does not consume ATP
Solute attaches tobinding siteon the carrier, carrier changesconformation, then releases solute on other side ofmembrane
36
37
Examples:
38
= resting potential
39
Each Na-K pump cycle:
Takes 2 K+in
-Moves ions fromlow concentration tohigher concentration
40
41
Secondary active transport
42
Involve TRANSPORT across the plasma membrane
Crucial to nerve and muscle function
43
Vesicular transport—moves large particles, fluid droplets, ornumerous molecules at once through the membrane
Vesicles = bubble-like enclosures of membrane; utilizes motorproteins energized by ATP
Endocytosis—vesicular processes that bring material into cell
Exocytosis—discharging material from the cell
44
© McGraw Hill
45
See poll for a quick quiz and answer
46
Note: A complete summary of cellular components can be found inTable 3.4in the reference book
47
Cytoskeleton—network of protein filaments and cylinders
Composed of: microfilaments, intermediate fibers,microtubules
48
Microfilaments
Intermediate filaments
Microtubules
49
Two kinds of inclusions
Never enclosed in a unitmembrane
Not essential for cell survival
50
Internal structures of a cell,carry out specialized metabolictasks
Membranous organelles
Non-membranous organelles
51
52
Golgi complex—a system of cisternsthat synthesizes carbohydrates andputs finishing touches on proteinsynthesis
53
Lysosomes—package of enzymes bound by a membrane
Functions
54
55
Nucleus—usually largest organelle (~ 5μmin diameter)
Nuclear envelope: perforated by nuclearpores formed by rings of proteins
Nucleoplasm—material in nucleus
56
Cells, shapes and sizes
Basic components of a cell
Plasma membrane
Membrane transport
Cytoskeleton
Organelles
Inclusions
Nucleus
57
Kinds of tissues in human body:
Epithelial tissue
Connective tissue
Nervous and Muscular (excitable) tissue
Tissue growth
Tissue development
Stem cells
Tissue repair and degeneration
Stem cell therapy, regenerative medicine, tissue engineering